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Soil and soil nutrient management in ofc production
This document discusses soil types and fertility management in Sri Lanka's dry zone. It describes the major soil types in the area, including Reddish Brown Earth (RBE) soils, Low Humic Gley soils, and issues affecting them like erosion, poor workability, and low fertility. It provides characteristics of RBE soils and discusses management practices to address depth limitations, erosion, workability, fertility, and irrigation on these soils. Salinity is also mentioned as a problem for some paddy soils in the dry zone, with causes and effects described.
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Soil and soil nutrient management in ofc production
- 1. Soil and Soil Fertility Management in OFC Production
- 2. Rocks Weathering ParentMaterials Soil Genesis Soil 1. Physical factors 2. Chemical factors 1. Climate 2. Parent material 3. Biosphere 4. Topography 5. Time
- 3. Components of Soil (Volume Basis) 25% Water 45% 25% Air 5% Composition varies – Place to place / Time to time Mineral Matter Organic Matter
- 4. Soil Properties Physical Properties Texture Structure Density Porosity Colour Moisture Content Water Holding Capacity Chemical Properties Nutrient Content pH Cation Exchange Capacity Electrical Conductivity Redox Potential Biological Properties Macro Organisms Micro Organisms
- 5. Soils of theDry Zone
- 6. Dry Zone ofSri Lanka Extent - 4.17 million ha. (Sri Lanka - 6.66 million ha.) Climate - <1750 mm (MARF) 25 - 30 C (MDT) Elevation - 0 – 300 m Land Form - Flat to Undulating (0 – 6 % Slope)
- 7. DL1a DL1b DL1c DL1d DL1e DL1f DL2&DL3 DL2a DL2b DL3 DL3&DL4 DL4 DL5 Agro-ecological Zones of Dry Zone of Sri Lanka Agro-ecological Regions of the Dry Zone of Sri Lanka
- 8. Soils of theDry Zone 1. Reddish Brown Earth 2. Low Humic Gley 3. Non Calcic Brown 4. Red Yellow Latasols 5. Sandy Regosols 6. Alluvial 7. Grumusols 8. Immature Brown Loam
- 9. Land Use onDry Zone Soils 1. Reddish Brown Earth – Maize / Grain legumes 2. Low Humic Glay – Paddy 3. Non Calcic Brown – Big onion / Red onion 4. Red Yellow Latasols – Cashew 5. Sandy Regosols – Coconut 6. Alluvial – Paddy 7. Grumusols – Paddy 8. Immature Brown Loam – Home garden
- 10. RBE (Rhodostalfs) Largest extent of the land in the dry zone Characteristic reddish brown colour Derived from Archacean rocks Soil catenary sequence RBE LHG Well Drained Imperfectly Drained Poorly Drained
- 11. Characteristics of RBESoils Physical Properties Soil Depth - Moderate (60 cm – 150 cm) Texture - Sandy clay loam Structure - Strong sub angular blocky Infiltration - 3 – 9 cm in 4 hours Available Moisture 130 – 170 mm/m Consistency - Hard when dry Slightly friable when moist Very sticky when wet
- 12. Chemical Properties SoilReaction- Mostly neutral (5.5 – 7 pH) Slightly acidic ( RF) Slightly alkaline ( RF) CEC - Relatively high (10 – 20 cmol/kg) BS - 60 – 90 % Nutrients - Relatively low N Relatively low P Moderate to high K om - Low (0.5 – 2 %) C / N - 8 - 12
- 13. Mineralogy Primary Minerals Ferromagnesian (Fe / Mg) Secondary (Clay) Minerals Kaolinite Illite Montmorillenite traces Land Use Natural Vegetation – Dry mixed evergreen forest Crops – Maize / Grain legumes
- 14. Problems Associated withRBE Soils in the Dry Zone • Depth • Erosion • Workability • Crusting • Fertility • Irrigation ?
- 15. Soil Depth Gravellayer – Quartsic / Ferralic Clay migration and deposition Hard pan formation Restrict soil depth Temporary submerged condition Restrict rooting depth Runoff Erosion
- 16. Erosion Poor aggregatestability Rain drop impact Splash erosion Surface sealing Low infiltration High surface runoff Soil erosion
- 17. Workability Kaolinitic clay– Very hard when dry Very sticky when wet Crusting Poor aggregate stability – Blocking spores with clay particles Crust formation under dry condition Evaporation Seed germination Greater use of energy
- 18. Soil Fertility Hightemperature Lack of top soil Low organic matter Nitrogen Microbial activities Sulphur / Posphorus Micro nutrients (Zn)
- 19. Irrigation Highererodability of soil Lower available moisture content Higher water losses within the soil system Higher ET rates Reduce the flexibility of designing surface irrigation systems
- 20. Management of RBESoils Depth Crop selection Deep ploughing Erosion 1.Correct use of land Land use classification Land capability classification
- 21. 2. Mechanical InfiltrationRun off Sub soil improvement Terraces Contour drains Contour earth bunds Terraces Contour bunds Terrace outlet channels Silt traps
- 22. 3. Agronomic Management Protection from rain drop impact Cropping systems Inter Mixed Alley Mulching Infiltration Dressing with om Mulching Deep ploughing Contour cropping Strip cropping Alley cropping
- 23. Workability Moisturemaintenance Timely cultivation Crusting Mulching - om / Soil Crop selection
- 24. Fertility Balanceduse of fertilizer Organic matter application Cropping systems • Alley • Inter • Mix • Crop rotation Different nutrient requirements Different rooting depths Nutrient movement to the top soil
- 25. Irrigation Dripirrigation Sprinkler irrigation Minimizing water losses Emphasis on crop water requirement
- 26. Low Humic GleySoils (Tropaqualfs) Second most extensive soil group in Sri Lanka Located at the foot slopes of the undulating landscape Characterized by the wetness or gleying through the profile Availability of calcite concretions Physical Properties Texture - Sandy clay to clay Structure - Sub angular blocky to massive WHC - Fairly good
- 27. Chemical Properties Soilreaction - Moderately alkaline Base saturation - 90-100 % Mineralogy Primary Minerals Calcite Secondary (Clay) Minerals Kaolinite Montmorillanite
- 28. Importance of SoilFertility Continuous cultivation Soil fertility degradation Soil Fertility Inherent capacity of a soil to supply nutrients to plants in 1) Adequate amounts 2) Suitable proportions
- 29. Soil Nutrients Macronutrients 1. Carbon 2. Hydrogen 3. Oxygen 4. Nitrogen 5. Phosphorus 6. Potassium 7. Calcium 8. Magnesium 9. Sulfur Micronutrients 1. Manganese 2. Copper 3. Zinc 4. Molybdenum 5. Boron 6. Chlorine 7. Iron
- 30. Nutrient Deficiencies Inadequateamounts and unsuitable proportions of soil nutrients Nutrient Deficiencies Identification of Deficiencies 1) Observation of visible symptoms 2) Plant tissue analysis 3) Soil analysis
- 31. Visual Observation ofNutrient Deficiencies 1) Leaf growth and colour 2) Plant height 3) Tillering 4) Root growth Important growth stages for identification of Deficiencies 1) Tillering stage 2) Flowering stage
- 32. Lemon greenish mature leaves Yellowish colour of the crop
- 33. Dark greenishcolour of leaves Retarted growth of the plant
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- 36. Exposure of the gravel layer
- 37. Siltation in water reservoirs
- 38. Fertility Upgrading CEC Improvement
- 39. Fertilizer Recommendation 1)Plant analysis Nitrogen recommendation 2) Soil analysis Available nutrient level in the soil Soil Test Based Fertilizer Recommendation
- 40. Nutrient Sources -Inorganic Nutrient Source Nutrient % N Urea 46 P Triple Super Phosphate 45 (P2O5) K Muriate of Potash 60 (K2O) Mg Dolomite 24 S Sulfur Powder - Mn Manganese Oxide 48 Cu Copper Sulfate 25 Zn Zinc Sulfate 35 B Borax 11 Fe Ferrous Sulfate 20
- 41. Nutrient Sources –Organic Green manure - Insitu – Sunhemp / Mukuna Exsitu – Gliricedia / Erithrina / Wild sunflower Crop residues Mulch Compost Farmyard manure
- 42. Other Major Problemsin Paddy Soils in Dry Zone Inland Salinity Accumulation of salts in soil pH EC (mmhos / cm) ESP (%) Salinity < 8.5 > 4 < 15 Alkalinity > 8.5 < 4 > 15
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- 45. Causal Factors ofSalinity 1) Irrigation 2) Higher evaporation with lower RF 3) Poor drainage 4) High salt content in the soil profile 5) Higher water table
- 46. Effects of salinity For Soil 1) Soil dispersion 2) Increase nitrogen losses due high pH 3) Organic matter mineralization due high pH For Plants 1) Physiological drought ness 2) Na / Cl toxicities 3) Difficulties in uptaking K, Ca, Zn
- 47. Remedial Measures 1)Drainage improvement 2) Washing out using quality water 3) Deep ploughing + smooth surface preparation 4) Water management 5) Mulching 6) Optimum nutrient supply 7) Organic matter usage 8) Gypsum amendment 9) Possible land use options
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